A. Field of Invention
This invention relates to hand exercisers and more particularly to exerciser devices for use in strengthening and therapy of the muscles of the forearm, wrist, hand and fingers.
B. Description of the Related Art
Hand exercise units, herein generally termed hand exercisers, are well known devices employed in the exercising of the muscles. The muscles are brought into operation in the forearm, hand, wrist and fingers as a result of contraction of the hand against the resistance of the hand exercise unit. This resistance is generally offered by steel elements under tension, such as springs, or by rubber balls to be gripped by the hand. These devices are intended to accommodate the hand but are generally limited to a single range of movement as the devices are forced to contract. This limited range of movement accordingly limits the benefit that can be achieved in carrying out exercises using such exercisers. The form of contraction resistance facility offered by the devices soon leads, on repeated use of the device, to those muscles which are exercised achieving a stale condition, nullifying any neuromuscular stimulation which has been achieved and correspondingly nullifying any progress which has taken place. It is a universally acknowledged fact in physiotherapy that neuromuscular progress is dependent on the ability to stimulate muscles from different angles with use of different exercises and training principles.
There are a few provisions for accommodating all the movements associated with the anatomy in question in a single hand exerciser. For example, U.S. Pat. No. 4,750,734 to Greenfield discloses a hand exerciser that provides for a wide variety of neuromuscular responses in physiotherapy and muscle building in a single device. The Greenfield patent further discloses that different resistance levels can be experienced within the hand exerciser depending on the location of the apertures with respect to the ring. However, the varying degree of resistance is limited due to the uniform nature of the material used to form the hand exerciser. The Greenfield patent also discloses that different resistances can be applied to different sectors on the web. However, this is achieved by using an external frame with adjustable tensioning devices. The present invention addresses these issues by creating a hand exerciser made from multiple materials wherein each material consists of a different elasticity modulus. Therefore, a wide range of resistance levels can be provided for with a single hand exerciser without the need for an external force to vary the resistance of the web.